Hey guys,
I have this cheap acoustic guitar from some obscure manufacturer called "GB&A", that my first music teacher recommended I get. I only went a few classes before I had to move to a different city, and I began to teach myself. It's not that great a guitar, but it's the only one I have. I recently noticed that the other acoustics I have played were easier to play in comparison. After a quick Google session, I learnt about action. The recommended action is about 3.28mm, but my guitar's low E string is 6mm off the fretboard at the twelfth fret. And I read that the guitar will be much better to play if I filed the saddle down, but there are no professionals where I live and I'd have to do it myself, and it seems risky. I just want to know if it's worth the risk, should I try it? If so, are there any precautions I should take?
Thanks in advance!
(I've attached a picture of the strings and fretboard at the fifth fret)
Just to give you some idea of the geometry. I set my action at a bit less than 2mm on the treble side, so if yours is 6 mm you would have to take (6-2) * 2 = 8 mm off the saddle to get something like my measurements. I doubt that you have anywhere near that much to work with. However, it is very important to get the neck relief right before lowering the saddle, as straightening the neck could win you a fair amount in terms of lower action. I assume that Frank's article in Frets covers this. If it doesn't, look up "neck relief adjustments".
Karan Menon You also need to show us a picture of the saddle. There needs to be a bunch showing above the bridge, or this could rapidly become a moot point, with the guitar unable to be fixed, without a neck reset.

The 3.28 estimate of action height you're working with, is very generous indeed. Most of us use far lower setting, about 2.5mm E-6 side.

No doubt though, if you are able to get it from 6mm down to 3mm or so, playing the guitar will be a lot more pleasurable. Provided of course, you do most of your playing in the open position. 3mm at the 12th would be a little rough trying to play lead.

You could always try a lighter string set, which might net you another 1 or 2/10mm reduction and an easier guitar to fret.
Last edited by Captaincranky at Nov 27, 2016,
Tightening the truss nut clockwise could straighten the neck some but you can;t count on it to fix a bent or out of angle neck if that is the case. Does the bridge look flat and level (unstressed)? Lower the saddle by sanding the bottom of it. I use a very slightly curved surface for the sandpaper to prevent the ends from getting cupped. If you do saddle work may as well get a decent material like bone or antler to improve sound, I'm partial to brass myself.

Yes, keeping the bottom of the saddle flat is important. I use the vise jaws as a stop, then finish on a file (making sure the file is actually flat!) rather than abrasive paper. If I did have to do it with abrasive paper, I would stick the paper to a sheet of glass with carpet tape.
How many times do i have to say this...

The truss rod has absolutely NOTHING to do with string height, or action. It has one function and one only, to set neck relief. It does not affect action or intonation. It's not hard to check to see if it actually needs adjusting. Put a capo on the 1st fret. Fret it at the fret where neck joins body. In the middle, about 7th or 8th fret, not critical, slip a business card under the strings. If the card just barely drags on the strings and fret, that's about right. That never changes no matter what you do to the saddle, you're using the string itself as a straight edge. You can set it before or after setting string height/action. I prefer before, that's just my preference.

Your main problem is the height of the strings, because the saddle is too tall. It can be sanded or filed, if you screw it up a new one is about 5 bucks. Once you know it needs to be sanded, figure out how much and use a pencil to mark the bottom about how much you want to take off. Start sanding. Once you get close to the pencil line, install and check. If you don't like it yet, sand some more. I don't know metric very well, I set mine about 1/8 inch, and I don't have a converter handy to consult. A bit lower on the treble string side.

Don't stress too much over a saddle, it's not expensive, a good bone one is only about 5 bucks. Make sure you can get one locally before you start tinkering. Or just get one and give it a try, and you still have the original to fall back on. Some are pre formed for the top that should match the neck radius or close, some are rectangular blocks, you have to finish the whole thing yourself. That's fun, but try it after you learn to do it with one already formed on top. Not hard to do either, use the old one to trace it on the new blank, get out a file. When you get close, switch to sandpaper, at least 180 grit. Always leave your line and try it, if you like it, the line is not hard to erase. Or sand off the side. If it needs more, take out the line. Work slow, nothing sucks more than sanding off too much.
Hmmm...I wonder what this button does...
Paleo Pete

Hmm, changing neck relief will change action height. If the neck relief increases, then the action height goes up. - Just think about the geometry of it, or give it a try on a guitar. If a guitar had a good action to start with, and the action has deteriorated it could well be that the neck relief has increased, and if this is the case, then the correct fix is to re-adjust the neck relief. In an acoustic there can be other factors that cause changes in action height, like deformity of the top, but in an electric, changing neck relief could the main cause of changed action height.

I do it in the following order:

1) Check and fix neck relief if necessary
2) Adjust saddle height
3) Adjust nut height

This is assuming that fretwork isn't needed.
I've done this for over 30 years, I'm not exactly running on a lack of knowledge.

Check this site, I can't find where I originally found it.


Read myth number one:

Myth Number One: You adjust playing action with the truss rod.

The truss rod may have a minor affect on action, but you can't tell it by playing it usually unless it's way off. What I said is correct. I've known it for a long time. The truss rod has one function and one only, to set neck relief. PERIOD.

Action is a combination of bridge height and nut height, the neck relief plays a part but a minor one. In practice, I've never seen changing neck relief affect string height to a degree I could detect, or a difference in action I could feel. I've been doing setups for well over 30 years, more detailed guitar work for about 30. I started to get serious about it because of an idiot here where I live who screwed up two guitar setups that both didn't need touching, nothing but string changes. He screwed up action, intonation, neck relief, pickup height, even tied the strings onto the tuning pegs with knots. He was working in a music store and I couldn't find a job anywhere...and didn't have a clue how to do it right. So I started to study it.

This is probably the most common guitar myth. The truss rod (neck relief) does not set action or intonation. It has a very minor affect on both, but is used ONLY to set neck relief. 90% of the time, I find it makes no difference to intonation my tuner can show, and no difference in action I can tell by playing it.

Good comprehensive article on truss rods and adjustment.


Their main page is one of my favorites for guitar info.

Hmmm...I wonder what this button does...
Paleo Pete

1) I've been doing it a little longer than you, up to and including nut slots, refretting, levelling and crowning

2) I can feel moderate changes in neck relief, especially with 13-56 strings on an acoustic, not so obvious with lighter electric strings

3) Resetting the neck relief correctly might be sufficient to correct the action height, depending on what caused the action height to be wrong in the first place

4) What I do not do is adjust. the saddle height before checking and making any necessary adjustments to neck relief

If setting up a guitar from scratch, the operational order I use is:

1) string and tune up and set approximate action height, intonation and nut slot height.

2) Set neck relief

3) Check action height and adjust the saddles as necessary

4) Retune, and set intonation and nut slot height.

5) Repeat steps 2, 3 and 4 as necessary

Now, let us suppose that I leave this newly-set-up guitar in its case for a few weeks, and week come back and find that the action has changed. What do I check first? The neck relief. If this is off, I re-adjust it. This might be sufficient to get the action back where it was. If it isn't, I adjust the saddle. Or, if the relief hasn't change, I assume that something else has moved and I just adjust the saddle

This scenario is pretty typical of what happens in my mate's music shop. He sets the guitars up from the factory and puts them on the rack, I come in and find that some of them don't feel good, so I check neck relief. Quite often if is either too much or too little, because it has changed since he did it.